DWR推送技术运用 |我的资源库露水湾

Java 代码

dwr推送技术的运用
先说说环境主要DWR3.0 spring3 springMVC hibernate
系统目标实现服务端主动向客户端推送数据，只是客户端打个某个页面，服务端定时向客户端推送新数据刷新客户端页面显示
集成 spring&MVC +hibernate 后配置DWR的步骤如下：
按惯例从 WEB.xml 讲起
添加DWR servlet
<listener>
<listener-class>com.gzeport.app.gps.dwr.AddScriptSessionListener</listener-class>
</listener>
///ScriptSession 将页面每个 session 放入一个 map
<!–dwr servlet–>
<servlet>
<servlet-name>dwr-invoker</servlet-name>
<servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
<init-param>
<param-name>debug</param-name>
<param-value>true</param-value>
</init-param>
<init-param>
<param-name>pollAndCometEnabled</param-name>
<param-value>true</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dwr-invoker</servlet-name>
<url-pattern>/dwr/*</url-pattern>
</servlet-mapping>
WEB.xml 过滤器配置好后编写推送程序
1—实体对象类这里随便的示例
import java.util.Date;
public class VehicleInfo {
private Long vehicleId;
private String vTKey;
private String plate;
private Date recvtime;
private Date gpstime;
private String lat;
private String lon;
private String height;
private String speed;
private String gpsSpeed;
private String dir;
private String mile;
private String eff;
private String alarm;
private String run;
private String statusChars;
private String mode;
private String tagChar;
private String protocol;
private String provider;
public Long getVehicleId() {
return vehicleId;
}
public void setVehicleId(Long vehicleId) {
this.vehicleId = vehicleId;
}
——
——这里省去好多 GET，SET 方法
——
public void setProvider(String provider) {
this.provider = provider;
}
}
2—ScriptSessionListener ScriptSession 监听类 AddScriptSessionListener.java
import java.util.HashMap;
import java.util.Map;
import org.directwebremoting.Container;
import org.directwebremoting.ScriptSession;
import org.directwebremoting.ServerContextFactory;
import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;
import org.directwebremoting.event.ScriptSessionEvent;
import org.directwebremoting.event.ScriptSessionListener;
import org.directwebremoting.extend.ScriptSessionManager;
public class AddScriptSessionListener implements ScriptSessionListener {
public static Map<String, ScriptSession> sc=new HashMap<String, ScriptSession>();
public void sessionCreated(ScriptSessionEvent ev) {
WebContext webContext = WebContextFactory.get();
sc.put(webContext.getSession().getId(), ev.getSession());
System.out.println(“add ———>”+ev.getSession().getId());
}
public void sessionDestroyed(ScriptSessionEvent ev) {
System.out.println(“remove ———>”+ev.getSession().getId());
}
}
3—推送程序类 DwrGpsHelper.java
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Map;
import java.util.concurrent.locks.ReentrantLock;
import org.directwebremoting.ScriptBuffer;
import org.directwebremoting.ScriptSession;
import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;
import org.directwebremoting.proxy.dwr.Util;
import com.gzeport.app.gps.dwr.AddScriptSessionListener;
import com.gzeport.app.gps.pojo.VehicleInfo;
import com.gzeport.app.gps.thread.ShipDataStore;
public class DwrGpsHelper {
private static ArrayList<VehicleInfo> messages = new ArrayList<VehicleInfo>();
private static ReentrantLock lock = new ReentrantLock(); //JDK5 锁
private ShipDataStore shipDataStore = null;
public void addMessage(){
try{
lock.lock();
System.out.println(“进入调度程序……….”);
messages = (ArrayList<VehicleInfo>) shipDataStore.getShipListData();
System.out.println(“取得数据:”+messages.size());
for(VehicleInfo vehicleInfo :messages){
if(vehicleInfo!=null){
System.out.println(“准备推送数据：”+vehicleInfo.getVTKey());
}
}
}catch(Exception ex){
ex.printStackTrace();
}finally{
lock.unlock();
}
Collection<ScriptSession> sessions =new LinkedList() ;
Map map=AddScriptSessionListener.sc;
Iterator<String> it = map.keySet().iterator();
StringBuffer sb = new StringBuffer();
int index =0;
if (it!=null){
while(it.hasNext()){
String key1 = it.next();
sessions.add((ScriptSession)map.get(key1));
}
}
System.out.println(“SSS–>”+sessions.size());
if(sessions!=null&&sessions.size()>0){
}else{
System.out.println(“sessions is null”);
}
Util utilAll = new Util(sessions);
//执行客户端脚本
ScriptBuffer script = new ScriptBuffer();
script.appendScript(“clientFunction(“)
.appendData(messages)
.appendScript(“);”);
for(ScriptSession session: sessions){
session.addScript(script);
}
//更新这些脚本 session 的一些元素
// utilAll.removeAllOptions(“messages”);
// utilAll.addOptions(“messages”, messages, “vTKey”, “statusChars”);
}
public ShipDataStore getShipDataStore() {
return shipDataStore;
}
public void setShipDataStore(ShipDataStore shipDataStore) {
this.shipDataStore = shipDataStore;
}
}
4—–DWR.xml 配置文件的配置
<!– 业务处理类交给 spring–>
<create creator=”spring” javascript=”dwrGpsHelper” scope=”application”>
<param name=”beanName” value=”dwrGpsHelper”/>
</create>
<!– convert 将 bean 的集合变成 javascript 中的对象数组–>
<convert converter=”bean” match=”com.gzeport.app.gps.pojo.VehicleInfo”>
<param name=”include” value=”alarm,dir,eff,mode,gpsSpeed,gpstime,height,lat,lon,mile,plate,protocol,provider,recvtime,
run,speed,statusChars,tagChar,vehicleId,vTKey”/>
</convert>
</allow>
5– spring bean 配置
<bean id=”dwrGpsHelper” class=”com.gzeport.app.gps.dwr.controller.DwrGpsHelper”>
<property name=”shipDataStore”>
<ref bean=”shipDataStore” />
</property>
<dwr:remote javascript=”dwrGpsHelper”>
<dwr:include method=”addMessage” />
</dwr:remote>
</bean>
6—-JSP 页面 showdata.jsp
<%@ page language=”java” pageEncoding=”UTF-8″%>
<%@ page import=”org.directwebremoting.ServerContextFactory” %>
<%@ page import=”org.directwebremoting.Container” %>
<%@ page import=”com.gzeport.app.gps.dwr.AddScriptSessionListener” %>
<%@ page import=”org.directwebremoting.extend.ScriptSessionManager” %>
<!DOCTYPE HTML PUBLIC “-//W3C//DTD HTML 4.01 Transitional//EN”>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+”://”+request.getServerName()+”:”+request.getServerPort()+path+”/”;
%>
<%String root=request.getContextPath();%>
<%
//添加监听器
Container container = ServerContextFactory.get().getContainer();
ScriptSessionManager manager = container.getBean(ScriptSessionManager.class);
manager.addScriptSessionListener(new AddScriptSessionListener());
%>
<html>
<head>
<script type=’text/javascript’ src='<%=root%>/dwr/engine.js’></script>
<script type=’text/javascript’ src='<%=root%>/dwr/util.js’></script>
<!– <script type=’text/javascript’ src='<%=root%>/dwr/interface/dwrVehicleInfoService.js’></script> –>
<script type=’text/javascript’ src='<%=root%>/dwr/interface/dwrGpsHelper.js’></script>
</head>
<!– 通过 dwr.engine.setActiveReverseAjax(true); 启动该页面的 Reverse Ajax 功能 –>
<body onload=”dwr.engine.setActiveReverseAjax(true);dwr.engine.setErrorHandler(function(){})”> //反转需要加上这两个
<!– <p>输入信息: <input id=”text” onkeypress=”dwr.util.onReturn(event, getMessage)” /> –>
<!– <input type=”button” value=”Send” onclick=”getMessage()()” /></p> –>
<!– –>
<p>从后台推送回的数据: </p>
<!– <input id=”text” /> –>
<script type=”text/javascript”>
function sendMessage() {
dwrVehicleInfoService.perform();
}
function putInfo(serverdata){
for(var i =0;i<serverdata.length;i++){
// alert(serverdata[i]);
var obj =dwr.util.toDescriptiveString(serverdata[i], 20);
// alert(dwr.util.toDescriptiveString(serverdata[i], 20));
}
// alert(serverdata.length);
}
function clientFunction(serverdata){
for(var i =0;i<serverdata.length;i++){
// alert(serverdata[i]);
var obj =dwr.util.toDescriptiveString(serverdata[i], 20);
// alert(dwr.util.toDescriptiveString(serverdata[i], 20));
}
alert(serverdata);
}
</script>
<hr/>
<!– <select id=”messages”></select> –>
<div id=”showdata”>
</div>
</body>
</html>
7—–配置一个调度器定时推送一次数据到页面
<!–Quartz –>
<!– 调度获取数据 –>
<bean id=”getDwrGpsHelperJobDetail” class=”org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean”
p:targetObject-ref=”dwrGpsHelper”
p:targetMethod=”addMessage” />
<bean id=”triggergetGpsShipDataCleaner” class=”org.springframework.scheduling.quartz.SimpleTriggerBean”
p:jobDetail-ref=”getDwrGpsHelperJobDetail”
p:startDelay=”20000″
p:repeatInterval=”15000″ />
<!– Spring 触发工厂 –>
<bean class=”org.springframework.scheduling.quartz.SchedulerFactoryBean”>
<property name=”triggers”>
<list>
<ref bean=”triggergetGpsShipDataCleaner”/>
<!– ….下面可以继续添加其他触发器 –>
</list>
</property>
</bean>
至此大致完成 dwr 推送程序的示例将每隔 15000 纳秒推送一次数据

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